I have had a set for over two decades. They have their good points, one being that they are entirely closed circumaural electrostatics, and that is a rare beast indeed. They have good bass and smooth midrange and very nice with most materials and especially pop/rock.
I don't rate them above even the old Stax Lambdas, which I also have, but the sound can vary with the manner of hook-up. They come with an old-fashioned transformer which is plugged into the power amp. More modern electrostatic units use a separate headphone amp. The transformer means one or more extra processing stages but may give you better dynamics, than most headphone amps, depending on your power amp. So I don't discount the possibility that with the right set-up and some mods, you could get some super sound.
I note that a reviewer on HEADWIZE reported that the foam backing in the cups shorts out with age, thereby screwing up the set. He recommended taking it out and cleaning the circuit board in place in each earcup and installing new foam.
Also the old, liquid-filled earpads tend to deteriorate, but can be replaced with more recent foam-filed pads of the same size.
I have been trying, unsuccesfully and without much real effort to get them to rum off an old Stax, low bias amp.
